modules/demux/xa.c

   1 /*****************************************************************************
   2  * xa.c : xa file demux module for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2005 Rémi Denis-Courmont
   5  *
   6  * Authors: Rémi Denis-Courmont
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU Lesser General Public License as published by
  10  * the Free Software Foundation; either version 2.1 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this program; if not, write to the Free Software Foundation,
  20  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  21  *****************************************************************************/
  22
  23 /*****************************************************************************
  24  * Preamble
  25  *****************************************************************************/
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <assert.h>
  32 #include <vlc_common.h>
  33 #include <vlc_plugin.h>
  34 #include <vlc_demux.h>
  35
  36 /*****************************************************************************
  37  * Module descriptor
  38  *****************************************************************************/
  39 static int  Open ( vlc_object_t * );
  40
  41 vlc_module_begin ()
  42     set_description( N_("XA demuxer") )
  43     set_category( CAT_INPUT )
  44     set_subcategory( SUBCAT_INPUT_DEMUX )
  45     set_capability( "demux", 10 )
  46     set_callback( Open )
  47 vlc_module_end ()
  48
  49 /*****************************************************************************
  50  * Local prototypes
  51  *****************************************************************************/
  52 static int Demux  ( demux_t * );
  53 static int Control( demux_t *, int i_query, va_list args );
  54
  55 typedef struct
  56 {
  57     es_out_id_t     *p_es;
  58
  59     unsigned int    i_data_size;
  60     unsigned int    i_block_frames;
  61     unsigned int    i_frame_size;
  62     unsigned int    i_bitrate;
  63
  64     date_t          pts;
  65 } demux_sys_t;
  66
  67 typedef struct xa_header_t
  68 {
  69     char     xa_id[4];
  70     uint32_t iSize;
  71
  72     uint16_t wFormatTag;
  73     uint16_t nChannels;
  74     uint32_t nSamplesPerSec;
  75     uint32_t nAvgBytesPerSec;
  76     uint16_t nBlockAlign;
  77     uint16_t wBitsPerSample;
  78 } xa_header_t;
  79
  80 #define HEADER_LENGTH 24
  81
  82 static_assert(offsetof(xa_header_t, wBitsPerSample) == 22, "Bad padding");
  83
  84 #define FRAME_LENGTH 28 /* samples per frame */
  85
  86 /*****************************************************************************
  87  * Open: check file and initializes structures
  88  *****************************************************************************/
  89 static int Open( vlc_object_t * p_this )
  90 {
  91     demux_t     *p_demux = (demux_t*)p_this;
  92     const uint8_t *peek;
  93
  94     /* XA file heuristic */
  95     if( vlc_stream_Peek( p_demux->s, &peek, 10 ) < 10 )
  96         return VLC_EGENERIC;
  97     if( memcmp( peek, "XAI", 4 ) && memcmp( peek, "XAJ", 4 ) &&
  98             memcmp( peek, "XA\0", 4 ) )
  99         return VLC_EGENERIC;
 100     if( GetWLE( peek + 8 ) != 1 ) /* format tag */
 101         return VLC_EGENERIC;
 102
 103     demux_sys_t *p_sys = vlc_obj_malloc( p_this, sizeof (*p_sys) );
 104     if( unlikely( p_sys == NULL ) )
 105         return VLC_ENOMEM;
 106
 107     /* read XA header*/
 108     xa_header_t xa;
 109
 110     if( vlc_stream_Read( p_demux->s, &xa, HEADER_LENGTH ) < HEADER_LENGTH )
 111         return VLC_EGENERIC;
 112
 113     es_format_t fmt;
 114     es_format_Init( &fmt, AUDIO_ES, VLC_CODEC_ADPCM_XA_EA );
 115
 116     msg_Dbg( p_demux, "assuming EA ADPCM audio codec" );
 117     fmt.audio.i_rate = GetDWLE( &xa.nSamplesPerSec );
 118     fmt.audio.i_bytes_per_frame = 15 * GetWLE( &xa.nChannels );
 119     fmt.audio.i_frame_length = FRAME_LENGTH;
 120
 121     fmt.audio.i_channels = GetWLE ( &xa.nChannels );
 122     fmt.audio.i_blockalign = fmt.audio.i_bytes_per_frame;
 123     fmt.audio.i_bitspersample = GetWLE( &xa.wBitsPerSample );
 124     fmt.i_bitrate = (fmt.audio.i_rate * fmt.audio.i_bytes_per_frame * 8)
 125                     / fmt.audio.i_frame_length;
 126
 127     /* FIXME: better computation */
 128     p_sys->i_data_size = xa.iSize * 15 / 56;
 129     /* How many frames per block (1:1 is too CPU intensive) */
 130     p_sys->i_block_frames = fmt.audio.i_rate / (FRAME_LENGTH * 20) + 1;
 131     p_sys->i_frame_size = fmt.audio.i_bytes_per_frame;
 132     p_sys->i_bitrate = fmt.i_bitrate;
 133
 134     msg_Dbg( p_demux, "fourcc: %4.4s, channels: %d, "
 135              "freq: %d Hz, bitrate: %dKo/s, blockalign: %d",
 136              (char *)&fmt.i_codec, fmt.audio.i_channels, fmt.audio.i_rate,
 137              fmt.i_bitrate / 8192, fmt.audio.i_blockalign );
 138
 139     if( fmt.audio.i_rate == 0 || fmt.audio.i_channels == 0
 140      || fmt.audio.i_bitspersample != 16 )
 141         return VLC_EGENERIC;
 142
 143     p_sys->p_es = es_out_Add( p_demux->out, &fmt );
 144     if( unlikely(p_sys->p_es == NULL) )
 145         return VLC_ENOMEM;
 146
 147     date_Init( &p_sys->pts, fmt.audio.i_rate, 1 );
 148     date_Set( &p_sys->pts, VLC_TICK_0 );
 149
 150     p_demux->pf_demux   = Demux;
 151     p_demux->pf_control = Control;
 152     p_demux->p_sys      = p_sys;
 153     return VLC_SUCCESS;
 154 }
 155
 156 /*****************************************************************************
 157  * Demux: read packet and send them to decoders
 158  *****************************************************************************
 159  * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 160  *****************************************************************************/
 161 static int Demux( demux_t *p_demux )
 162 {
 163     demux_sys_t *p_sys = p_demux->p_sys;
 164     block_t     *p_block;
 165     int64_t     i_offset = vlc_stream_Tell( p_demux->s );
 166     unsigned    i_frames = p_sys->i_block_frames;
 167
 168     if( p_sys->i_data_size > 0 &&
 169         (i_offset - HEADER_LENGTH) >= p_sys->i_data_size )
 170     {
 171         return VLC_DEMUXER_EOF;
 172     }
 173
 174     p_block = vlc_stream_Block( p_demux->s, p_sys->i_frame_size * i_frames );
 175     if( p_block == NULL )
 176     {
 177         msg_Warn( p_demux, "cannot read data" );
 178         return VLC_DEMUXER_EOF;
 179     }
 180
 181     i_frames = p_block->i_buffer / p_sys->i_frame_size;
 182     p_block->i_dts = p_block->i_pts = date_Get( &p_sys->pts );
 183     es_out_SetPCR( p_demux->out, p_block->i_pts );
 184     es_out_Send( p_demux->out, p_sys->p_es, p_block );
 185
 186     date_Increment( &p_sys->pts, i_frames * FRAME_LENGTH );
 187
 188     return VLC_DEMUXER_SUCCESS;
 189 }
 190
 191 /*****************************************************************************
 192  * Control:
 193  *****************************************************************************/
 194 static int Control( demux_t *p_demux, int i_query, va_list args )
 195 {
 196     demux_sys_t *p_sys  = p_demux->p_sys;
 197
 198     return demux_vaControlHelper( p_demux->s, HEADER_LENGTH,
 199         p_sys->i_data_size ? (int64_t)HEADER_LENGTH + p_sys->i_data_size : -1,
 200                                   p_sys->i_bitrate, p_sys->i_frame_size,
 201                                   i_query, args );
 202 }